Sample analyzer and a sample analyzing method

ABSTRACT

Herewith disclosed is a sample analyzer comprising: a measurement section configured to perform a measurement on a sample and generate a measurement value according to the concentration of an analyte in the sample; a memory storing a calibration curve; an analysis section; an output section; and an instruction receiver. When the instruction receiver receives an instruction to perform a diluting measurement on a calibration sample, the measurement section dilutes the calibration sample by a predetermined ratio and performs a measurement on the diluted calibration sample, and the analysis section determines the concentration of the analyte in the diluted calibration sample by applying a measurement value obtained from the diluted calibration sample to the calibration curve. Information generated based on the determined concentration and the known concentration is output.

RELATED APPLICATIONS

This application is a divisional patent application of U.S. patentapplication Ser. No. 13/744,904, filed Jan. 18, 2013, which claimspriority under 35 U.S.C. §119 to Japanese Patent Application No.2012-009775 filed on Jan. 20, 2012, the entire content of which ishereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a sample analyzer capable of dilutingand measuring a sample. The present invention also relates to a sampleanalyzing method.

BACKGROUND OF THE INVENTION

Sample analyzers such as immunoanalyzers determine the concentration ofa component to be measured in a sample by applying a measurement valuesuch as the light absorption to a calibration curve that has beenprepared beforehand using a standard sample of known concentration.However, when the concentration of the component in the sample to bemeasured is too high and exceeds the concentration range covered by thecalibration curve, it becomes difficult to accurately determine theconcentration of the component to be measured even by applying themeasurement value to the calibration curve. In this case, the sample isdiluted to obtain a concentration that is within the concentration rangecovered by the calibration curve, so that the concentration of thecomponent in the sample being measured can be determined by applying themeasurement value of the diluted sample to the calibration curve.

Japanese Laid-Open Patent Publication No. 2001-228155 discloses a methodof determining antibody or antigen content in serum. According to thismethod, the concentration of the measurement target component containedin the sample is determined by diluting the sample of unknownconcentration by a predetermined factor, applying the measured value ofthe diluted sample to the calibration curve and converting the measuredvalue to the concentration of the measurement target component in thediluted sample, then multiplying the converted concentration by thedilution ratio in order to obtain the original concentration of themeasurement target component contained in the undiluted sample.

Various sources of error are inherent in the diluting measurement of thesample. For example, there is a very small error between the setdilution ratio and the actual dilution ratio when the apparatus dilutesthe sample. Dilution may be repeated for a sample of extremely highconcentration, and this error may increase according to the repeateddilutions. Furthermore, affinity between a reagent and a dilutingsolution may produce variance in linearity of dilution. That is,depending on the affinity of the reagent and the diluting solution, thereagent is not necessarily diluted at desired ratio.

SUMMARY OF THE INVENTION

A first aspect of the present invention is a sample analyzer comprising:a measurement section configured to perform a measurement on a sampleand generate a measurement value according to the concentration of ananalyte in the sample; a memory storing a calibration curve that definesa relationship of a measurement value and a concentration of theanalyte; an analysis section; an output section; and an instructionreceiver for receiving an instruction to perform a measurement of asample, wherein, when the instruction receiver receives an instructionto perform a diluting measurement on a calibration sample that containsa known concentration of the analyte, the measurement section dilutesthe calibration sample by mixing a diluting fluid and the calibrationsample by a predetermined ratio and performs a measurement on thediluted calibration sample; the analysis section determines theconcentration of the analyte in the diluted calibration sample byapplying a measurement value obtained from the diluted calibrationsample to the calibration curve; and the output section outputsinformation generated based on the determined concentration and theknown concentration.

A second aspect of the present invention is a sample analyzercomprising: a measurement section configured to perform a measurement ona sample to quantify an analyte in the sample; and a computer; whereinthe computer is programmed to perform (A) a calibration operation, and(B) a sample analysis operation, (A) the calibration operationcomprising: (A-1) causing the measurement section to perform ameasurement on a plurality of calibration samples, each containing ananalyte of known concentration; (A-2) causing the measurement section todilute a calibration sample containing an analyte of known concentrationX at a predetermined ratio with a diluting fluid and to perform ameasurement on the diluted calibration sample; (A-3) preparing acalibration curve based on the known concentrations of the calibrationsamples and the measurement results of (A-1); and (A-4) applying themeasurement result of (A-2) to the prepared calibration curve todetermine a converted concentration X0, (B) the sample analysisoperation comprising: (B-1) causing the measurement section to dilute asample to be measured at a predetermined ratio with a diluting fluid andto perform a measurement on the diluted sample; (B-2) applying themeasurement result of (B-1) to the calibration curve prepared todetermine a concentration Y0; and (B-3) using the concentration Y0 andthe ratio of the known concentration X and the converted concentrationX0 to determine the sample concentration Y.

A third aspect of the present invention is a sample analyzing methodcomprising the steps of: diluting a calibration sample containing ananalyte of known concentration X at a predetermined ratio by mixing witha diluting fluid, and measuring the diluted calibration sample;converting a measurement value of the diluted calibration sample in thecomputer to a converted concentration X0 by applying the measurementvalue to a previously prepared calibration curve; diluting a sample tobe measured by the predetermined ratio by mixing with a diluting fluid,and measuring the diluted sample; converting a measurement value of thediluted sample to a converted concentration Y0 in the computer byapplying the measurement value of the diluted sample to the calibrationcurve; and determining a concentration Y of the analyte contained in thesample to be measured in the computer by multiplying the concentrationY0 by the ratio of the known concentration X and the convertedconcentration X0.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the general structure of animmunoanalyzer as an embodiment of the sample analyzer of the presentinvention;

FIG. 2 is a plan view of the immunoanalyzer of FIG. 1;

FIG. 3 shows the structure of the control device;

FIG. 4 is a flow chart of the sample measurement when the sample is notdiluted;

FIG. 5 is a flow chart of the sample measurement when the sample isdiluted;

FIG. 6 shows the flows of the calibration curve preparation and thecorrection coefficient calculation;

FIG. 7 shows an example of a calibration curve;

FIG. 8 shows the flow of the concentration conversion of a dilutedsample;

FIG. 9 shows a display example of a display input section;

FIG. 10 shows an example of a calibration curve preparation requestscreen; and

FIG. 11 shows an example of a calibration result screen.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of the sample analyzer of the present invention aredescribed hereinafter with reference to the accompanying drawings. FIG.1 is a perspective view showing the general structure of theimmunoanalyzer 1. FIG. 2 is a plan view of the immunoanalyzer 1 ofFIG. 1. The general structure of the immunoanalyzer 1 is first describedbelow.

[General Structure of Immunoanalyzer 1]

The immunoanalyzer 1 examines various items such as hepatitis type-B,hepatitis type-C, tumor marker, and thyroid hormone contained in a serumsample (hereinafter referred to simply as “sample”) by utilizing anantigen/antibody reaction. The immunoanalyzer 1 has a measurementsection 2, sample transport section (sampler) 3, and a control device 4.The measurement section 2 is communicably connected to the sampletransport section 3 and the control device 4 with communication enabled.The sample transport section 3 is configured to transport a rack holdinga plurality of test tubes containing sample collected from a subject.The control device 4 has a display input section 410 that includes atouch panel.

As shown in FIG. 2, the measurement section 3 has a sample dispensingarm 5, R1 reagent dispensing arm 6, R2 reagent dispensing arm 7, R3reagent dispensing arm 8, reactor 9, cuvette supplier 10, primary BF(bound free) separation section 11, secondary BF separation section 12,pipette tip supplier 13, detection section 14, R4/R5 reagent supplier15, reagent installation section 16, disposal section 17, and controller200. The sample transport section 3 is configured to transport a rackholding a plurality of test tubes containing unprocessed sample.

At first, the immunoanalyzer 1 mixes the sample to be measured with abuffer solution (R1 reagent). The immunoanalyzer 1 adds a reagent (R2reagent) containing magnetic particles carrying capture antibody forbinding to an antigen contained in the sample to the obtained mixture.The immunoanalyzer 1 attracts the magnetic particles in the mixture by amagnet (not shown in the drawing) of the primary BF (bound free)separation section 11 and removes the component that has not been boundto the capture antibody when magnetic particles are attracted. Then theimmunoanalyzer 1 adds a labeling antibody (R3 reagent) to the mixture.The labeling antibody is an antibody carrying an enzymatic marker. Afterthe labeling antibody (R3 reagent) has been added, the immunoanalyzer 1attracts the magnetic particles in the mixture by a magnet (not shown inthe drawing) of the secondary BF (bound free) separation section 12 andremoves the R3 reagent containing the unreacted labeling antibody fromthe mixture when the magnetic particles are attracted. Theimmunoanalyzer 1 then adds a dispersant (R4 reagent) and a luminescentsubstrate (R5 reagent), which luminesces by a reaction with theenzymatic marker carried by the labeling antibody to the mixture. Theimmunoanalyzer 1 then measures the amount of light produced by thereaction between the marker of the labeling antibody and the luminescentsubstrate. The antigen contained in the sample bound to the labelingantibody can be quantified through this process.

The cuvette supplier 10 is configured to accommodate a plurality ofcuvettes, and sequentially supplies the cuvettes one by one to thedischarge position 1 b where the sample dispensing arm 5 dispenses aquantity of sample.

A pipette 6 a for aspirating and dispensing R1 reagent is attached tothe R1 reagent dispensing arm 6. The R1 reagent dispensing arm 6aspirates the R1 reagent in the reagent installation section 16 anddispenses (discharges) the aspirated R1 reagent to a cuvette placed atthe discharge position 1 b via the pipette 6 a.

The pipette tip supplier 13 moves a plurality of loaded pipette tips(not shown in the drawing) one by one to the tip installation position(not shown in the drawing). Thereafter, the pipette tip is mounted onthe pipette end of the sample dispensing arm 5 at the tip installationposition.

The sample dispensing arm 5 aspirates the sample in the test tube movedto the sample aspirating position 1 a by the sample transport section 3using the installed pipette tip. This aspiration is accomplished througha hole 31 a formed in a cover 31 that covers the transport path of thesample transport section 3. The sample dispensing arm 5 dispenses(discharges) the aspirated sample into a cuvette at the dischargeposition 1 b. Prior to discharging the sample to the cuvette, the R1reagent was previously dispensed to the cuvette by the R1 reagentdispensing arm 6. Thereafter, the cuvette is moved to the reactor 9 by acatcher (not shown in the drawing) of the R1 reagent dispensing arm 6.

A pipette 7 a for aspirating and discharging R2 reagent is attached tothe R2 reagent dispensing arm 7. The R2 reagent dispensing arm 7aspirates the R2 reagent in the reagent installation section 16 anddispenses (discharges) the aspirated R2 reagent to a cuvette containingthe R1 reagent and the sample.

The reactor 9 has an annular shape so as to circumscribe the reagentinstallation section 16, which is circular, as shown in the drawing. Thereactor 9 has a plurality of cuvette holders 9 a arranged at equalspacing along the exterior. Cuvettes set in the cuvette holders 9 a areheated to approximately 42 degrees centigrade. Hence, the heatingpromotes a reaction of the various reagents and the sample in thecuvette. The reactor 9 is configured to be rotatable in a clockwisedirection (arrow A1 direction), and moves the cuvette set in the cuvetteholder 9 a to each processing position where various processes (reagentdispensing and the like) are performed.

The cuvette containing the sample, R1 reagent and R2 reagents is movedby a catcher (not shown in the drawing) from the reactor 9 to theprimary BF separation section 11. Primary BF separation is performed inthe primary BF separation section 11. The component in the sample thathas not bonded to the capture antibody (R2 reagent) is thus removed fromthe sample within the cuvette. Having completed primary BF separation,the cuvette is returned to the reactor 9 by the catcher (not shown).

A pipette 8 a for aspirating and discharging R3 reagent is attached tothe R3 reagent dispensing arm 8. The R3 reagent dispensing arm 8 usesthe pipette 8 a to aspirate the R3 reagent set at the reagentinstallation section 16. The R3 reagent dispensing arm 8 also uses thepipette 8 a to dispense (discharge) the aspirated R3 reagent into thecuvette which was moved from the primary BF separation section 11 to thereactor 9.

The cuvette containing the R3 reagent and the sample is moved from thereactor 9 to the secondary BF separation section 12 by a catcher (notshown in the drawing). Secondary BF separation is performed in thesecondary BF separation section 12. The R3 reagent including theunreacted labeled antibody is thereby removed. Having completedsecondary BF separation, the cuvette is returned to the reactor 9 by thecatcher (not shown).

The R4/R5 reagent supplier 15 sequentially dispenses R4 and R5 reagentsto the cuvette.

The reagent installation section 16 holds R1 reagent, R2 reagent, and R3reagent for each measurement item. The reagent installation section 16is further provided with a sample diluting fluid (BSA buffer) used todilute samples when performing diluting measurement of a sample.

The detection section 14 obtains the amount of light produced during thereaction process between the luminescent substrate (R5 reagent) and thelabeling antibody (R3 reagent) bonded to the antigen of the amplesubjected to predetermined processing with a photomultiplier tube. Thedetection section 14 transmits the signals corresponding to the amountof light to the controller 200.

The disposal section 17 is a section for the disposal of cuvettes andwaste fluid within the cuvettes after detection is completed, and thedisposal section has an aspiration part (not shown) for aspirating wastefluid within the cuvette, and a disposal hole (not shown). Afterdetection, the cuvette is moved from the detection section 14 to thedisposal section 17 by a catcher (not shown), the waste fluid within thecuvette is aspirated by the aspiration part and the cuvette from whichthe waste fluid has been aspirated is discarded through the disposalhole in the disposal section 17.

The controller 200 of the measurement section 2 is configured by a CPU,and a memory section such as a ROM, RAM, hard disk, and controls eachpart of the measurement section 2 according to the signal received fromthe main body 400 of the control device 4. The controller 200 receivesthe signals sent from the detection section 14, converts the signals tonumerical values, and analyzes the converted measurement values. Thecontroller 200 transmits the analysis results to the main body 400 ofthe control device 4.

Structure of the Control Device

FIG. 3 shows the structure of the control device 4 in the immunoanalyzer1. The control device 4 is configured by a personal computer thatincludes a main body 400, and display/input part 410. The main body 400has a CPU 401, ROM 402, RAM 403, hard disk 404, reading device 405, I/Ointerface 406, image output interface 407, and communication interface408.

The CPU 401 is capable of loading a computer program stored in the ROM402 and executing the computer program in the RAM 403. The RAM 403 isused when reading the computer program stored in the ROM 402 andrecorded on the hard disk 404. The RAM 403 is also used as the work areaof the CPU 401 when the CPU 401 executes the computer programs.

An operating system and application programs, as well as the data usedwhen executing the operating system and application programs that areexecuted by the CPU 401, are installed on the hard disk 404.

The reader 405 is a CD drive or DVD drive capable of reading computerprograms and data recorded on a recording medium.

The I/O interface 406 receives the signals output from the display/inputsection 410. The image output interface 407 outputs image signalscorresponding to the image data to the display/input section 410. Thedisplay/input section 410 displays images based on the image signalsreceived from the image output interface 407, and outputs instructionsreceived from the user through the screen of the display/input section410 through the I/O interface 406.

Note that a keyboard image is displayed for receiving input text on thedisplay/input section 410 when numerical values are input via thedisplay/input section 410. The user inputs the numerical value bypressing the numbers displayed on the image of the keyboard.

The communication interface 408 transmits signals from the main body 400to the controller 200 of the control section 2 on the main body 400side, and receives signals sent from the controller 200 of the controlsection 2.

[Sample Measurement Flow (without Sample Dilution)]

An embodiment of the method of measuring component in a sample collectedfrom a subject using the previously mentioned immunoanalyzer 1 isdescribed below. The description pertains to measuring a component in anundiluted sample based on the flow chart shown in FIG. 4.

The controller 200 of the measurement section 2 first receives ameasurement start signal from the main body 400 of the control device 4,and in step S401 the various drive mechanisms of the sample dispensingarm 5 and the like are placed on standby at the origin position, thenthe cuvette supplier 10 is actuated to deliver a new cuvette to thedischarging position 1 b of the sample dispensing arm 5.

In step S402, the controller 200 of the measurement section 2 rotatesthe R1 reagent dispensing arm 6 until the tip of the pipette 6 a of theR1 reagent dispensing arm 6 is positioned above the R1 reagent disposedon the reagent installation section 16, and aspirates a predeterminedamount of R1 reagent using the pipette 6 a. Thereafter, the R1 reagentdispensing arm 6 is rotated until the tip of the pipette 6 a ispositioned above the cuvette arranged at the discharging position 1 b,and the aspirated R1 reagent is dispensed into the cuvette.

In step S403, the controller 200 of the measurement section 2 aspiratesa predetermined amount of sample in the test tube that has been moved tothe sample aspirating position 1 a by the sample transport section 3using the pipette tip mounted on the pipette end of the sampledispensing arm 5 at the tip installation position. Thereafter, thesample dispensing arm 5 is rotated until the pipette tip mounted on thepipette end of the sample dispensing arm 5 is positioned above thecuvette disposed at the discharging position 1 b, and the aspiratedsample is dispensed into the cuvette.

In step S404, the controller 200 of the measurement section 2 actuates acatcher (not shown in the drawing) of the R2 reagent dispensing arm 6 tomove the cuvette disposed at the discharging position 1 b to apredetermined cuvette holding section 9 a of the reactor 9.

In step S405, the controller 200 of the measurement section 2 rotatesthe R2 reagent dispensing arm 7 until the tip of the pipette 7 a of theR2 reagent dispensing arm 7 is positioned above the R2 reagent disposedon the reagent installation section 16, and aspirates a predeterminedamount of R2 reagent using the pipette 7 a. Thereafter, the R2 reagentdispensing arm 7 is rotated until the tip of the pipette 7 a ispositioned above the cuvette arranged at the cuvette holding position 9a, and the aspirated R2 reagent is dispensed into the cuvette containingthe R1 reagent and sample.

In step S406, the controller 200 of the measurement section 2 actuates acatcher (not shown in the drawing) to move the cuvette containing thesample and R1 and R2 reagents from the cuvette holding position 9 a ofthe reactor 9 to the primary BF separation section 11.

In step S407, the controller 200 of the measurement section 2 performsprimary BF separation to remove the component in the sample that is notbonded to the capture antibody from the sample in the cuvette.

In step S408, the controller 200 of the measurement section 2 actuates acatcher (not shown in the drawing) to move the cuvette disposed at theprimary BF separation section 11 after primary BF separation has beenperformed to the cuvette holding position 9 a of the reactor 9.

In step S409, the controller 200 of the measurement section 2 rotatesthe R3 reagent dispensing arm 8 until the tip of the pipette 8 a of theR3 reagent dispensing arm 8 is positioned above the R3 reagent disposedon the reagent installation section 16, and aspirates a predeterminedamount of R3 reagent using the pipette 8 a. Thereafter, the R3 reagentdispensing arm 8 is rotated until the tip of the pipette 8 a is moved toa position above the cuvette arranged at the cuvette holding position 9a of the reactor 9, and the aspirated R3 reagent is dispensed into thecuvette.

In step S410, the controller 200 of the measurement section 2 actuates acatcher (not shown in the drawing) to move the cuvette containing thedispensed R3 reagent from the cuvette holding position 9 a of thereactor 9 to the secondary BF separation section 12.

In step S411, the controller 200 of the measurement section 2 performssecondary BF separation to remove the R3 reagent containing theunreacted labeling antibody from the cuvette.

In step S412, the controller 200 of the measurement section 2 actuates acatcher (not shown in the drawing) to move the cuvette disposed at thesecondary BF separation section 12 after secondary BF separation hasbeen performed to the cuvette holding position 9 a of the reactor 9.

In step S413, the controller 200 of the measurement section 2 actuates acatcher (not shown in the drawing) to move the cuvette from the cuvetteholding position 9 a of the reactor 9 to the R4/R5 reagent supplier 15.Thereafter, the R4/R5 reagent supplier 15 is actuated to dispense R4reagent into the cuvette.

In step S414, the controller 200 of the measurement section 2 actuates acatcher (not shown in the drawing) to move the cuvette disposed at theR4/R5 reagent supplier 15 to the cuvette holding position 9 a of thereactor 9. Thereafter, the R4/R5 reagent supplier 15 is actuated todispense R5 reagent into the cuvette containing the R4 reagent.

In step S415, the controller 200 of the measurement section 2 actuates acatcher (not shown in the drawing) to move the cuvette containing thedispensed R4 and R5 reagents held at the cuvette holding position 9 a ofthe reactor 9 to the detection section 14. Thereafter, the amount oflight produced in the reaction process between the marker of labelingantibody and the luminescent substrate is measured by a photomultipliertube. The signal corresponding to the measured amount of light istransmitted to the controller 200, converted to a numerical value andstored in memory.

In step S416, the measured cuvette is moved from the detection section14 to the disposal section 17 by a catcher (not shown in the drawing),and in the disposal section 17 the sample (waste liquid) remaining inthe cuvette is aspirated by the aspirating unit, then the empty cuvetteis discarded through the disposal hole of the disposal section 17.

[Sample Measurement Flow (With Sample Dilution)]

The following description pertains to measuring a component in a samplediluted 40 times based on the flow chart shown in FIG. 5. Theimmunoanalyzer of the present embodiment measures measurement items suchas PIC (plasmin inhibitor complex) tumor marker, CEA (carcinoembryonicantigen), AFP (alpha fetoprotein), infection marker HBsAg (hepatitistype B antigen examination), HBsAb (hepatitis type B antibodyexamination) and the like. These measurement items, and especially fortumor marker, the concentration of the component to be measured is veryhigh in the sample of a positive patient, and the measured values mayexceed the range covered by the calibration curve (over range). In suchcases, the analyte is diluted prior to measurement to ensure themeasured value of the analyte is within the range covered by thecalibration curve. The flow of the series of diluting and measuring theanalyte is described below based on the flow shown in FIG. 5.

Note that in the embodiment shown in FIG. 5 steps S501 through S506replace steps S401 through S405 of FIG. 4, and following step S506 thesame operations or processes are performed as in steps S404 through S416of FIG. 4. Therefore, steps S501 through S506 specific to the embodimentof FIG. 5 are described below and the steps S404 through S416 duplicatedin FIG. 4 are omitted for the sake of simplicity.

The controller 200 of the measurement section 2 first receives ameasurement start signal from the main body 400 of the control device 4,and in step S501 the various drive mechanisms of the sample dispensingarm 5 and the like are placed on standby at the origin position, thenthe cuvette supplier 10 is actuated to deliver a new cuvette (dilutioncuvette) to the discharging position 1 b of the sample dispensing arm 5.

In step S502, the controller 200 of the measurement section 2 rotatesthe R1 reagent dispensing arm 6 until the tip of the pipette 6 a of theR1 reagent dispensing arm 6 is positioned above the sample dilutingfluid disposed on the reagent installation section 16, and aspirates apredetermined amount (for example, 195 μl) of diluting fluid using thepipette 6 a. Thereafter, the R1 reagent dispensing arm 6 is rotateduntil the tip of the pipette 6 a is positioned above the dilutioncuvette arranged at the discharging position 1 b, and the aspirateddiluting fluid is dispensed into the cuvette.

In step S503, the controller 200 of the measurement section 2 aspiratesthe sample in the test tube that has been moved to the sample aspiratingposition 1 a by the sample transport section 3 using the pipette tipmounted on the pipette end of the sample dispensing arm 5 at the tipinstallation position. Thereafter, the sample dispensing arm 5 isrotated until the pipette tip mounted on the pipette end of the sampledispensing arm 5 is positioned above the dilution cuvette disposed atthe discharging position 1 b, and a predetermined amount (for example 5μl) of the aspirated sample is dispensed into the dilution cuvette.Thus, the sample is diluted 5/(195+5)=40 times by the diluting fluid.

In step S504, the controller 200 of the measurement section 2 actuatesthe cuvette supplier 10 and sets a new cuvette (measurement cuvette) atthe discharging position 1 b of the sample dispensing arm 5. Note thatthe measurement cuvette and the dilution cuvette are same kind ofcuvette and that both are supplied from the cuvette supplier 10.Although the used dilution cuvette is transported along the same pathwayas the measurement cuvette, BF separation, reagent dispensing, andoptical measurement processes are fully skipped, and ultimately thedilution cuvette is discarded in the disposal section 17 without opticalmeasurement.

In step S505, the controller 200 of the measurement section 2 rotatesthe R1 reagent dispensing arm 6 until the tip of the pipette 6 a of theR1 reagent dispensing arm 6 is positioned above the R1 reagent disposedon the reagent installation section 16, and aspirates a predeterminedamount of R1 reagent using the pipette 6 a. Thereafter, the R1 reagentdispensing arm 6 is rotated until the tip of the pipette 6 a ispositioned above the measurement cuvette arranged at the dischargingposition 1 b, and the aspirated R1 reagent is dispensed into themeasurement cuvette.

Then, in step S506, the controller 200 of the measurement section 2aspirates the sample that has been diluted 40 fold within the dilutioncuvette using the pipette tip mounted on the pipette end of the sampledispensing arm 5. Thereafter, the sample dispensing arm 5 is rotateduntil the pipette tip mounted on the pipette end of the sampledispensing arm 5 is positioned above the measurement cuvette disposed atthe discharging position 1 b, and a predetermined amount of theaspirated diluted sample is dispensed into the measurement cuvette.

After step S506, steps S404 through S416 are performed and the amount oflight is measured by the detection section 14. The signal correspondingto the measured amount of light is transmitted to the controller 200,converted to a numerical value and stored in memory. The measurementvalue (numerical value) corresponds to the concentration of the antigen(component) contained in the dilution sample. This value is applied tothe calibration curve prepared in a manner described later, to obtainthe converted concentration.

[Calibration Curve Preparation and Correction Coefficient Calculation]

In the present embodiment, a calibration curve is prepared using aplurality of calibration samples containing known concentrations ofmeasurement components prior to measuring the concentration ofcomponents in a measurement sample. A calibration curve is prepared foreach measurement item. For example, a calibration curve is thereforeprepared for the HBsAg measurement item using a plurality of calibrationsamples containing known concentrations of HBsAg, and a calibrationcurve is also prepared for the PIC measurement item using a plurality ofcalibration samples containing known concentrations of PIC. Correctioncoefficients are calculated to be used in the concentration calculationwhen a dilution sample is measured using the calibration curve. Thecalibration curve and the correction coefficient are stored in the ROM202 of the controller 200.

FIG. 10 shows an example of a calibration curve preparation requestscreen shown on the display input section 410. The calibration curvepreparation request screen 100 includes an item selection column A11,calibrator selection column A12, number input column A13, dilutingmeasurement number input column A14, OK button A15, and cancel buttonA16. The calibration curve preparation request screen 100 functions asan interface for receiving an instruction of a calibration curvepreparation from the user to the immunoanalyzer 1, and also functions asan interface for receiving an instruction of a calibration samplediluting measurement from a user to the immunoanalyzer 1 when a numberis entered in the diluting measurement number input column A14.

FIG. 6 shows examples of the flows of the calibration curve preparationand the correction coefficient calculation. The user inputs whether toprepare a calibration curve of a desired measurement item (whether toperform calibration for any measurement item) from the item selectioncolumn A11 in the calibration curve preparation request screen 100 ofFIG. 10. The item selection column A11 is a pull-down menu, and displaysa plurality of measurement items in a pull down format by clicking thecursor on the column. The user specifies one measurement item from thelist. In the example shown in FIG. 10, PIC is selected as themeasurement item.

The user then selects the type of calibration sample to prepare thecalibration curve from the calibrator selection column A12, and checksthe check box corresponding to the desired calibration sample. In theexample of FIG. 10, five calibration samples C0 through C4 includingmeasurement component of known concentration are selected. Note that theconcentration (hereinafter referred to as “indicated value”) of themeasurement component included in calibration samples C0 through C4 ism0 through m4, where m0<m1<m2<m3<m4. The number of calibration samplesused when preparing a calibration curve is not limited to five, and maybe four or less than four, or six or more than six. The indicated valuesof calibration samples C0 through C4 may be input beforehand by the userentering the value through the display input section 410 beforehand, orinput beforehand by reading barcodes attached to the calibration samplesC0 through C4 via a barcode reader that is not shown in the drawing,then storing the information in the controller 200 of the measurementsection 2.

The user then inputs the number of measurements for calibration for eachof the selected calibration samples C0 through C4 from the number inputcolumn A13. In the example of FIG. 10, a number is entered to measureeach calibration sample one time.

The user then choices the calibration sample to be used for dilutingmeasurements among the calibration samples C0 through C4, and determinesthe number of such measurements. The user enters this information fromthe diluting measurement number input column A14. In the example of FIG.10, C4 is selected as the calibration sample to be used for dilutingmeasurement, and two is entered as the number of diluting measurements.

When the above information is entered via the calibration curvepreparation request screen 100 and the user selects the OK button A15,the input information is stored and calibration begins. When the cancelbutton A16 is selected, the entered information is deleted.

The user sets the calibration samples C0 through C4 in a sample rack andsets the sample rack in the sample transport section 3 beforecalibration. When the sample rack is set and the OK button A15 isselected on the calibration curve preparation request screen 100, themeasurement section 2 start the measurement of the calibration sampleaccording to the flow shown in FIG. 6.

In step S601, the controller 200 of the measurement section 2sequentially measures the calibration samples C0 through C4 according tothe previously described steps S401 through S415 (refer to FIG. 4), andobtains the measurement values (amount of light) F0 through F4. In theexample of FIG. 10, each calibration sample is measured once since themeasurement number of each calibration sample is [1]. Note that eachcalibration sample also may be measured several times (for example,three times) to improve the accuracy of the obtained calibration. Insuch case the measurement value of each calibration sample is theaverage value of several measurement values obtained by a plurality ofmeasurements.

In step S602, the controller 200 of the measurement section 2 prepares adiluted calibration sample of user-specified calibration sample CX (X isselected from 0 through 4) which contains known concentration (referredas mX). The user-specified calibration sample CX is diluted 40 times.Measurements according to steps S501 through S506 and steps S404 throughS415 (refer to FIG. 5) are performed, and the measurement value FX′ isobtained and stored in memory. Since C4 is selected as the calibrationsample to be used for diluting measurement in the example of FIG. 10, adiluted calibration sample is prepared by diluting C4 by 40 times andmeasurement is performed on it.

Although steps S601 and S602 are listed as separate steps in thedrawing, in the actual measurement flow, step S602 is performedconsecutively to the measurement of the calibration sample correspondingto step S601. For example, if the calibration sample C3 is specified fordiluting measurement, the diluting measurement of C3 is performedfollowing the undiluted measurement of C3 in step S601, and thereafterthe measurement of C4 begins.

In step S603, the controller 200 of the measurement section 2 reads thestored indicated values m0 through m4 and prepares the calibration curvesuch as shown in FIG. 7 from the read indicated values m0 through m4 andthe measurement values F0 through F4 obtained in step S601, then storesthe prepared calibration curve together with the lot number of thecalibration sample used to prepare the calibration curve in the ROM 202of the controller 200. To facilitate understanding, in the example shownin FIG. 7, the intersections of the known concentration m and themeasured value F are plotted on a straight line, however in an actualcase, the plurality of intersections may not be linear. Therefore,approximate algorithms like as the least squares method or the like isused to determine the regressive line and regressive curve as thecalibration curve.

In step S604, the controller 200 of the measurement section 2 appliesthe measurement value FX′ measured in step S602 to the calibration curveprepared in step S603 to obtain the converted concentration mX′. Whenthe diluting measurements of a calibration sample have been performedtwice or more, the converted concentration mX′ is calculated as theaverage value of the plurality of converted concentration values.

In step S605, the controller 200 of the measurement section 2 reads theindicated value mX stored in correspondence with the dilutingmeasurement calibration sample CX, calculates the correction coefficientR=mX/mX′ as the concentration ratio from the read indicated value mX andthe converted concentration mX′ obtained in step S604, and stores thecalculated correction coefficient R and the prepared calibration curvein the ROM 202 of the controller 200 in step S606. The calculation ofthe correction coefficient R is illustrated by way of example pertainingto the obtained measurement values shown in Table 1.

TABLE 1 Measurement Converted value of diluting concentrationCalibration sample C0 C1 C2 C3 C4 measurement for C4 of diluted C4Indicated value 0 0.01 0.1 0.3 1.2 Measurement First 523 47,921 496,8821,499,902 5,537,675 143,763 0.0315 value (count measurement value)Second 142,024 0.0313 measurement Average 523 47,921 496,882 1,499,9025,537,675 142,894 0.0314

In this example, the indicated value of the calibration sample C4 is1.2, and since the average value of the converted concentration valuesof the diluted calibration sample C4 is 0.0314, the dilution correctioncoefficient R is 38.21 according to the following equation.

Dilution correction coefficient R=1.2/0.0314=38.21.

In step S607, the display input section 410 displays a calibrationresult screen 300 to show the correction coefficient R. FIG. 11 shows acalibration result screen 300 that appears on the display input section410. The calibration result screen 300 has a correction coefficientdisplay column B11 where the correction coefficient R calculated in stepS605 is displayed.

In the example of Table 1, the dilution correction coefficient R is38.21 when the dilution ratio is set at 40 times, hence, in such casethe error is 4.3% relative to expected value of 40. If the error fromthe dilution correction coefficient R displayed in the correctioncoefficient display column B11 is calculated and the error is within theacceptable range, the user selects the validate button B12 on the screen300 to validate (approve) the calibration curve and the correctioncoefficient R.

On the other hand, when the dilution ratio is 40 times and thecorrection coefficient R is, for example, 30, there is an error of 25%relative to the expected value 40. In this case several causes should beconsidered, such as an error due to the quantifying accuracy of thepipette 5 a of the sample dispensing arm 5 of the measurement section 2or from the quantifying accuracy of the pipette 6 a of the R1 reagentdispensing arm 6. Or there may be a problem in the diluting ability ofthe sample diluting fluid, hence, affinity of the sample diluting fluidand the reagent R1 may not be so good that the dilution linearity islost. These factors can be mitigated by the user readjusting thedispensing mechanisms to increase the quantifying accuracy, or replacingthe sample diluting fluid.

According to the above embodiment, the user can check whether themeasurement section 2 is performing the desired dilution accurately byconfirming whether the dilution correction coefficient R is within thedesired range on the calibration result screen 300.

[Diluted Sample Measurement and Concentration Conversion]

Obtaining the concentration of a diluted sample using the calibrationcurve and correction coefficient determined according to the flow shownin FIG. 6 is described below referring to the flow chart of FIG. 8. Notethat in the description of FIG. 8 the correction coefficient R is thecorrection coefficient determined at a dilution ratio of 40, and thedilution ratio of the sample is also 40.

First, in step S701, the controller 200 of the measurement section 2dilutes a sample by 40 times to prepare a diluted sample according tosteps S501 through S506 and performs a measurement on the diluted sampleaccording to steps S404 through S415 to obtain the measurement value Ft.

In step S702, the controller 200 of the measurement section 2 appliesthe measured value Ft obtained in step S701 to the calibration curveprepared in step S603 and stored in the ROM 202 of the controller 200 toacquire the converted concentration mt.

In step S703, the controller 200 of the measurement section 2 calculatesthe concentration mt0 by multiplying the converted concentration mtobtained in step S702 by the correction coefficient R calculated andstored in the ROM 202 of the controller 200 in step S605.

In step S704, the controller 200 of the measurement section 2 transmitsthe calculated concentration mt0 to the control device 4, and the mainbody 400 of the control device 4 shows the received result(concentration mt0) on the display input section 410. FIG. 9 shows apartial example of the display on the display input section 410. Theresult (concentration) of each measurement item is displayed in themeasurement result column. When the sample has been diluted andmeasured, the dilution ratio is displayed in the dilution ratio column[1/40] shows that the sample was diluted by 40 times. And [1/1] showsthat the sample was not diluted. When a diluting measurement has beenperformed, the dilution correction column shows whether a concentrationcalculation has been performed using the correction coefficient R ormodified correction coefficient R′ (described later). Mark is displayedwhen concentration calculation has been performed using the correctioncoefficient R or the modified correction coefficient R′, and the columnremains blank when concentration calculation has not been performedusing the correction coefficient R or the modified correctioncoefficient R′. Whether the concentration calculation is performed usingthe correction coefficient R or the modified correction coefficient R′can be specified by the user for each measurement item in a screen (notshown in the drawings) used to specify the start of a samplemeasurement.

According to the above embodiment, the user can check whether themeasurement section 2 is performing dilution with the desired dilutionaccuracy by the user confirming whether the dilution correctioncoefficient R is displayed on the calibration result screen 300 with thepost dilution concentration and indicated value as comparative results,and that the dilution correction coefficient R is within the desiredrange. An accurate sample concentration can be determined by performingthe diluting measurement of the sample and confirming the dilutionaccuracy.

Modifications

Note that the present invention is not limited to the above describedembodiment and may be variously modified insofar as such modificationare within the scope of the claims.

In the above embodiment, the dilution ratio (M1) of a sample to bemeasured and the dilution ration (M2) of the calibration sample used fordetermining the dilution correction coefficient R is same as 40 times.Even if the dilution ratios of M1 and M2 are different, the convertedconcentration mt0 of the sample may be calculate as shown below.

The concentration mt0 can be calculated by multiplying the convertedconcentration mt by the modified correction coefficient R′ that derivesfrom the correction coefficient R. The modified correction coefficientR′ may be a coefficient obtained by, multiplying the dilution correctioncoefficient R by M1/M2. For example, when the calibration sampledilution ratio (M2) is 40 and the sample dilution ratio (M1) is 80,M1/M2 is 80/40=2. Then, the modified correction coefficient R′ isobtained by doubling the correction coefficient R.

When the sample dilution ratio is M2×M2, the modified correctioncoefficient R′ is obtained by squaring the correction coefficient R(R²). For example, when the calibration sample dilution ratio is 40 andthe sample dilution ratio is 1600, the square of the dilution correctioncoefficient R is used as the modified correction coefficient R′.

In the above embodiment the dilution accuracy is evaluated by the usercomparing the diluting measurement ratio and the displayed dilutioncorrection coefficient R when the dilution correction coefficient R isshown in the calibration result screen 300, however, the presentinvention is not limited to this method. For example, when thecalibration sample C4 indicated value is 1.2 and the average value ofthe concentration conversion value is calculated as 0.0314 for thediluted calibration sample C4, these values may be displayed incomparable manner. Furthermore, the controller 200 may be configured todetermine whether the ratio of these values exceeds a predeterminedvalue (for example, the set dilution ratio), and displays thedetermination result.

Not only the dilution correction coefficient R, but also the dilutionratio can be displayed in calibration result screen 300. In a furthermodification, the dilution correction coefficient R is calculated andthe error between the dilution correction coefficient R and the dilutionratio is calculated and displayed on the calibration result screen 300.In yet another modification, when the calculated error is outside apredetermined range, a warning is shown on the screen, and an audiblesound is output to alert the user.

Although the correction coefficient is calculated using one calibrationsample selected by the user from among the plurality of calibrationsamples used to prepare the calibration curves in the above embodiment,the correction coefficient also may be determined for two or morecalibration samples. For example, when the dilution measurements areperformed on the calibration samples C1 through C3, the correctioncoefficients R1, R2, and R3 are determined as [32], [35], and [34]respectively. And the dilution ratio is 40. In this case, [33.7] iscalculated as the average value of [32], [35], and [34]. This value isset as the correction coefficient R for diluting measurements where thedilution ratio is 40. In another case, for example, a sample is dilutedand measured, and the converted concentration value is between the knownconcentration m1 of the calibration sample C1 and the knownconcentration m2 of the calibration sample C2 when the measurement valueis applied to the calibration curve. In this case, the average value ofthe correction coefficient of the calibration sample C1 [32] and thecorrection coefficient of the calibration sample C2 [35] is 33.5 andthis value is set as the correction value. Or the correction coefficient[32] is used when the converted concentration value is near m1, whereasthe correction coefficient [35] is used when the converted concentrationvalue is near m2.

Although the correction coefficient is determined using one calibrationsample selected among the calibration samples C1 through C4 used toprepare the calibration curve in the above embodiment, the presentinvention is not limited to this arrangement inasmuch as the correctioncoefficient also may be determined using a special calibration sample C5for determining a correction coefficient.

Although the correction coefficient obtained from measuring the dilutedcalibration sample is stored in the memory section ROM 202 in the aboveembodiment, the correction coefficient not always have to be determinedand stored in the memory. The concentrations of components contained inthe sample can be calculated on the basis of a first concentration of adiluted sample and a known concentration of a calibration sample, and asecond concentration of a diluted calibration sample. That is, when thedilution ratio of the sample is designated M1 and the dilution ratio ofthe calibration sample is designated M2, the concentration of thecomponent contained in the sample can be calculated as [the firstconcentration]×(known concentration of calibration sample/secondconcentration)×(M1/M2).

Although the above embodiment is described only in terms of using thepredetermined correction coefficient R to determine the concentration ofa sample, a mode for calculating the dilution ratio by multiplicationusing a conventional method where the dilution ratio is used on behalfof the correction coefficient, and a mode for calculating using acorrection coefficient may be selectable. In this case, which mode wasused to calculate the concentration is preferably displayed in anidentifiable manner on the measurement result display screen as in FIG.9.

Although the above embodiment pertains to an immunoanalyzer thatexamines various items such as hepatitis type B, hepatitis type C, tumormarker, and thyroid hormone using a sample such a blood as an example ofa sample analyzer, the present invention is not limited to this exampleinasmuch as the invention is applicable diluting measurement of samplesin apparatuses for measuring the concentrations of components in thesample using a calibration curve.

1.-12. (canceled)
 13. A sample analyzer comprising: a measurementsection configured to perform a measurement on a sample to quantify ananalyte in the sample; and a computer; wherein the computer isprogrammed to perform (A) a calibration operation, and (B) a sampleanalysis operation, (A) the calibration operation comprising: (A-1)causing the measurement section to perform a measurement on a pluralityof calibration samples, each containing an analyte of knownconcentration; (A-2) causing the measurement section to dilute acalibration sample containing an analyte of known concentration X at apredetermined ratio with a diluting fluid and to perform a measurementon the diluted calibration sample; (A-3) preparing a calibration curvebased on the known concentrations of the calibration samples and themeasurement results of (A-1); and (A-4) applying the measurement resultof (A-2) to the prepared calibration curve to determine a convertedconcentration X0, (B) the sample analysis operation comprising: (B-1)causing the measurement section to dilute a sample to be measured at apredetermined ratio with a diluting fluid and to perform a measurementon the diluted sample; (B-2) applying the measurement result of (B-1) tothe calibration curve prepared to determine a concentration Y0; and(B-3) using the concentration Y0 and the ratio of the knownconcentration X and the converted concentration X0 to determine thesample concentration Y.
 14. The sample analyzer of claim 13, wherein (A)the calibration operation comprises: displaying on a display of thecomputer a screen for selecting a calibration sample to be measured in(A-2) among the plurality of calibration samples.
 15. The sampleanalyzer of claim 14, wherein the screen comprises a menu specifying thenumber of measurements of the calibration sample in (A-2), and thecomputer performs the number of measurement in (A-2) specified by themenu and determines the concentration X0 in (A-4) based on the averagevalue of the measurement results of the measurements of (A-2). 16.-20.(canceled)
 21. The sample analyzer of claim 13, wherein when preparingthe calibration curve, the measurement section performs a plurality ofmeasurements of each of a plurality of calibration samples; and thecomputer is programmed to determine an average value of a plurality ofmeasurement values obtained by performing a plurality of measurements asa representative measurement value of one calibration sample, andprepares the calibration curve based on the representative measurementvalue and the known concentration of the calibration sample.
 22. Thesample analyzer of claim 13, wherein the computer includes a displayunit, and the display unit shows the concentration of the analyte in thesample determined using the correction coefficient together withinformation indicating that the concentration was determined based onthe correction coefficient.
 23. The sample analyzer of claim 13, whereinthe measurement section generates the measurement value by opticallymeasuring the analyte in the sample.
 24. The sample analyzer of claim13, wherein the computer includes a display unit, and the display unitshows a screen including the calculated concentration ratio and thedilution ratio used to performing the dilution measurement on thecalibration sample to determine the concentration ratio.
 25. The sampleanalyzer of claim 13, wherein the computer outputs a warning when arelationship between the concentration ratio and the dilution ratio doesnot satisfy a predetermined condition.
 26. The sample analyzer of claim13, further comprising a transport section configured to transport arack capable of holding a plurality of containers containing sample,wherein when a plurality of containers containing a calibration sampleare placed in the rack and the rack is transported to the measurementsection by the transport section, the measurement section consecutivelyperforms measurement of the calibration samples to prepare thecalibration curve, and performs the dilution measurement of at least oneof the calibration samples.
 27. The sample analyzer of claim 13, whereinthe sample is a serum sample.
 28. The sample analyzer of claim 13further comprising: a reagent installation section for setting a reagentcausing an antigen-antibody reaction between the analyte and thereagent; and a reagent dispensing arm configured to dispense the reagentset in the reagent installation section.
 29. The sample analyzer ofclaim 28, wherein the analyte is an antigen; and the reagent is areagent including an antibody which is capable of binding to theantigen.
 30. The sample analyzer of claim 29, wherein the antibody is alabeling antibody.
 31. The sample analyzer of claim 30, wherein thereagent installation section is capable of setting a luminescentsubstrate which luminesces by a reaction with the labeling antibody. 32.A sample analyzer comprising: a measurement section configured toperform a measurement on a sample to quantify an analyte in the sample;and a computer; wherein the computer is programmed to perform (A) acalibration operation, and (B) a sample analysis operation, (A) thecalibration operation comprising: (A-1) causing the measurement sectionto perform a measurement on a plurality of calibration samples, eachcontaining an analyte of known concentration; (A-2) causing themeasurement section to dilute a calibration sample containing an analyteof known concentration X at a predetermined ratio with a diluting fluidand to perform a measurement on the diluted calibration sample; (A-3)preparing a calibration curve based on the known concentrations of thecalibration samples and the measurement results of (A-1); and (A-4)applying the measurement result of (A-2) to the prepared calibrationcurve to determine a converted concentration X0, (B) the sample analysisoperation comprising: (B-1) causing the measurement section to dilute asample to be measured at a predetermined ratio with a diluting fluid andto perform a measurement on the diluted sample; (B-2) applying themeasurement result of (B-1) to the calibration curve prepared todetermine a concentration Y0; and (B-3) using the concentration Y0 andthe ratio of the known concentration X and the converted concentrationX0 to determine the sample concentration Y, wherein the measurementsection generates the measurement value by optically measuring theanalyte in the sample, wherein the sample analyzer, further comprises: areagent installation section for setting a reagent causing anantigen-antibody reaction between the analyte and the reagent; and areagent dispensing arm configured to dispense the reagent set in thereagent installation section.
 33. The sample analyzer of claim 32,wherein the analyte is an antigen; and the reagent is a reagentincluding an antibody which is capable of binding to the antigen. 34.The sample analyzer of claim 33, wherein the antibody is a labelingantibody.
 35. The sample analyzer of claim 34, wherein the reagentinstallation section is capable of setting a luminescent substrate whichluminesces by a reaction with the labeling antibody.
 36. The sampleanalyzer of claim 32, wherein the sample is a serum sample.
 37. A sampleanalyzer comprising: a measurement section configured to perform ameasurement on a sample to quantify an analyte in the sample; and acomputer; wherein the computer is programmed to perform (A) acalibration operation, and (B) a sample analysis operation, (A) thecalibration operation comprising: (A-1) causing the measurement sectionto perform a measurement on a plurality of calibration samples, eachcontaining an analyte of known concentration; (A-2) causing themeasurement section to dilute a calibration sample containing an analyteof known concentration X at a predetermined ratio with a diluting fluidand to perform a measurement on the diluted calibration sample; (A-3)preparing a calibration curve based on the known concentrations of thecalibration samples and the measurement results of (A-1); and (A-4)applying the measurement result of (A-2) to the prepared calibrationcurve to determine a converted concentration X0, (B) the sample analysisoperation comprising: (B-1) causing the measurement section to dilute asample to be measured at a predetermined ratio with a diluting fluid andto perform a measurement on the diluted sample; (B-2) applying themeasurement result of (B-1) to the calibration curve prepared todetermine a concentration Y0; and (B-3) using the concentration Y0 andthe ratio of the known concentration X and the converted concentrationX0 to determine the sample concentration Y, wherein the sample analyzerof claim 1, further comprises: a reagent installation section forsetting a reagent causing an antigen-antibody reaction between theanalyte and the reagent; and a reagent dispensing arm configured todispense the reagent set in the reagent installation section, whereinthe sample is a serum sample.